# renef_jni_new_string

Creates a new Java String object in the target process.

Agent View of the PolicyLayer registry record for `renef_jni_new_string`. HTML page: https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-jni-new-string

## Facts

- Tool: `renef_jni_new_string`
- Server: Renef (`ahmeth4n/renef-mcp`) — https://policylayer.com/tools/ahmeth4n-renef-mcp.md
- Homepage: https://github.com/Ahmeth4n/renef-mcp
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "renef_jni_new_string",
    "arguments": {}
  }
}
```

## Why renef_jni_new_string is rated High

This tool performs dynamic memory manipulation and Java object instantiation in a target process without user consent or control. While not destructive in itself, it enables code execution within the target application's context, allowing modification of application behavior, injection of data, and potential privilege escalation.

From the tool's own definition: "Creates a new Java String object in the target process — directly manipulates the memory and runtime state of a running Android application through JNI (Java Native Interface) interception, enabling arbitrary code execution effects."

## Use case

AI agents invoke renef_jni_new_string to trigger actions in Renef. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Renef:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "renef_jni_new_string": {
      "limits": [
        {
          "counter": "renef_jni_new_string_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Renef (74)

- `renef_hard_reset` — Destructive — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-hard-reset.md
- `renef_jni_delete_ref` — Destructive — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-jni-delete-ref.md
- `renef_port_forward_remove` — Destructive — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-port-forward-remove.md
- `renef_port_forward_remove_all` — Destructive — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-port-forward-remove-all.md
- `renef_server_kill` — Destructive — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-server-kill.md
- `adb_selinux_disable` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/adb-selinux-disable.md
- `adb_selinux_enable` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/adb-selinux-enable.md
- `adb_start_app_am` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/adb-start-app-am.md
- `adb_start_app_monkey` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/adb-start-app-monkey.md
- `adb_stop_app_am` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/adb-stop-app-am.md
- `renef_attach` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-attach.md
- `renef_cli_reset` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-cli-reset.md
- `renef_exec` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-exec.md
- `renef_hook_generate` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-hook-generate.md
- `renef_hook_java` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-hook-java.md
- `renef_hook_native` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-hook-native.md
- `renef_load_script` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-load-script.md
- `renef_mem_write` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-mem-write.md
- `renef_mem_write_u16` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-mem-write-u16.md
- `renef_mem_write_u32` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-mem-write-u32.md
- `renef_mem_write_u64` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-mem-write-u64.md
- `renef_mem_write_u8` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-mem-write-u8.md
- `renef_memory_patch` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-memory-patch.md
- `renef_port_forward_add` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-port-forward-add.md
- `renef_server_deploy` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-server-deploy.md
- `renef_server_restart` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-server-restart.md
- `renef_server_start` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-server-start.md
- `renef_spawn` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-spawn.md
- `renef_zero_copy_multiline_exec` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/renef-zero-copy-multiline-exec.md
- `run` — Execute — https://policylayer.com/tools/ahmeth4n-renef-mcp/run.md
- …and 44 more: https://policylayer.com/tools/ahmeth4n-renef-mcp.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=ahmeth4n-renef-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/ahmeth4n-renef-mcp